Bakersfield Night Sky – January 3, 2009
By Nick Strobel
Happy New Year! Today-tomorrow mark our closest distance to the Sun (the "perihelion" point of our orbit). Venus is the brightest star-like object in our evening sky---look toward the southwest (see chart A). Only the waxing crescent Moon will outshine Venus (full Moon on the 10th). Venus is in the zodiac constellation of Aquarius. Closer to the horizon are Mercury and Jupiter. Mercury is pulling away from Jupiter after their end-of-2008 conjunction. Tomorrow evening Mercury will be as far east of the Sun as it will get before scooting back into the glare of the Sun. This greatest eastern separation is called "greatest eastern elongation". Venus will be at its greatest eastern elongation on January 14th and set almost 4 hours after sunset. After that date it will slide back closer to the Sun. Note that the chart does not show the position of the Sun that will be a lot closer to Jupiter in our sky on the 14th.
To understand what's going on with Mercury and Venus, look at the inset graphic at the lower left corner of chart A. This shows a top-down or "orrery" view of the inner solar system with the planet orbits plotted. When Venus is at its greatest elongation from the Sun, the angle formed by Venus-Earth-Sun is the greatest it gets (same explanation for Mercury). Over the following weeks Venus will catch up to the Earth and pass by it. As Venus passes by the Earth it will appear even brighter in our sky because it will be so much closer to us. In a telescope Venus will appear as a crescent that gets thinner the closer it gets to the Sun as viewed from the Earth.
Saturn continues to shine below the tail of Leo in the pre-dawn sky---look high in the southwest at around 6 AM (see chart B). The waning gibbous Moon will pass below it on January 15th. Saturn is drifting backwards= westward (retrograde) as the Earth catches up to it in our faster, smaller orbit. Saturn will retrograde until mid-May.
Want to see more of the
stars at night and save energy? Shield your lights so that the light
only goes down toward the ground. See www.darksky.org for how.
Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com
last updated: January 7, 2009
Webpage contact: Nick Strobel